This invention relates to the production of synthetic, crystalline ferrierite, an alumino-silicate zeolite. Ferrierite is relatively scarce in nature but does occur in bedded deposits in the Western United States. Natural ferrierite has the general formula (Na,K).sub.0.5.sub.-4 Ca.sub.0.sub.-1 Mg.sub.0.5.sub.-3 (Al.sub.4.sub.-7 Fe.sub.0.sub.-1 Si.sub.27.sub.-31.sub.') O.sub.72 . 18-23 H.sub.2 O
where the sum of the moles of alkali and alkaline earth oxides equal the sum of the moles of alumina and ferria, (Na.sub.2 O + K.sub.2 O + CaO + MgO) .congruent. (Al.sub.2 O.sub.3 + Fe.sub.2 O.sub.3), and (Si + Al + Fe) = 36. Natural ferrierite from Kamloops Lake, British Columbia, Canada has been shown by P. A. Vaughan, Acta Crystallographica 21, 983 (1966), to be orthorhombic with the space group I 2/M 2/M 2/M. Natural ferrierites from various localities do not have exactly the same X-ray powder pattern, but the X-ray powder pattern of ferrierite from each locality fits the theoretically allowed lines for the space group 2/M, 2/M, 2/M, as shown below in Table A. Synthetic strontium ferrierites of the approximate composition SrO:Al.sub.2 O.sub.3 : 7-9 SiO.sub.2, the X-ray powder patterns of which also fit the allowed lines, have been described in the literature by R. M. Barrer and D. J. Marshall, Journal of the Chemical Society 1964. 485. Synthetic strontium and calcium ferrierite were made at 350.degree.-370.degree.C and 1,020-1,632 atmospheres by D. B. Hawkins, Materials Research Bulletin, 2 951 (1967). Also, synthetic sodium ferrierite was made by E. E. Senderov, Geochemistry (English Translation) 9. 848 (1963). Synthesis of strontium ferrierites by Barrer and Marshall were carried out at temperatures of 260.degree., 340.degree. and 380.degree.C at pressures of 39, 144 and 235 atmospheres, respectively. Even though such high temperatures as 340.degree. and 380.degree. were employed, the synthesis of strontium ferrierite required 2-4 days. Twenty days were required to crystallize strontium ferrierite from a 1.5 SrO:1.0 Al.sub.2 O.sub.3 : 9SiO.sub.2 : 500H.sub.2 O slurry at 260.degree.C.
The synthesis of strontium ferrierite, reported by Barrer and Marshall, at 340.degree. and 380.degree. C are relatively difficult, and the product ferrierite is frequently contaminated with impurities. By using the seeding technique, described below, we have reduced the temperatures, pressures and times required for synthesis; also we have greatly improved the reliability of the process.
Furthermore, no natural ferrierite has been shown to contain substantial amounts of strontium or lithium or both. Table B shows that samples of natural ferrierite from five localities are mainly sodium, potassium, magnesium, calcium aluminosilicate hydrates, with some substitution of iron for aluminum.
TABLE A __________________________________________________________________________ COMPARISON OF D SPACINGS OF TWO NATURAL AND SYNTHETIC STRONITIUM FERRIERITES WITH THE ALLOWED LINES FERRIERITE Ferrierite FERRIERITE, SYNTHETIC Theoretical Kamloops Lake Agoura, Ca. STRONTIUM for I 2/M 2/M 2/M B.C., Canada FERRIERITE* Where a = 19.16 b = 14.13 and c = 7.49 Relative Relative Relative hkl dA dA Intensity dA Intensity dA Intensity __________________________________________________________________________ 110 11.37 11.3 20 11.3 3 -- -- 200 9.58 9.61 100 9.47 50 9.49 75 020 7.06 7.00 30 7.07 38 7.07 20 101 6.98 -- -- 6.96 15 011 6.62 6.61 20 6.59 3 6.61 55 310 5.82 5.84 50 5.75 15 5.77 15 220 5.69 -- -- 5.64 14 -- -- 211 5.44 -- -- -- -- 5.43 5 121 4.964 4.96 10- -- -- 4.96 15 301 4.860 -- -- -- -- -- -- 400 4.790 4.80 10- 4.75 2 4.76 15 130 4.574 4.58 10- 4.56 1 -- -- 321 4.004 -- -- -- -- -- -- 031 3.987 3.99 90 3.98 35 3.99 45 420 3.965 -- -- 3.94 35 3.94 35 411 3.880 3.88 10 -- -- 3.86 25 330 3.791 3.791 20 3.78 65 3.78 50 002 3.745 -- -- -- -- 3.74 10 510 3.698 3.69 50 3.66 12 3.67 30 231 3.681 -- -- -- -- 112 3.557 3.54 80 -- -- 3.555 10 040 3.532 -- -- 3.54 100 3.536 90 202 3.488 3.49 80 3.48 18 3.483 100 501 3.411 3.42 20 -- -- 3.389 15 240 3.314 3.31 20 3.31 35 3.313 20 600 3.193 3.20 10 -- -- -- -- 141 3.152 3.15 30 -- -- 3.142 55 312 3.149 -- -- 3.14 12 -- -- 521 3.072 3.07 30 -- -- 3.058 45 431 3.064 -- -- 3.05 12 -- -- 530 2.972 2.97 30 -- -- 2.960 25 402 2.950 -- -- 2.945 11 2.938 25 620 2.910 2.90 20 -- -- 2.897 35 422 2.722 2.72 20 -- -- 2.715 30 051 2.644 2.64 20 2.644 7 2.646 15 350 2.584 2.58 30 2.582 10 2.583 10 701 2.571 -- -- -- -- -- -- __________________________________________________________________________ *Barrier and Marshall, American Mineralogist 50, 484 (1965)
TABLE B __________________________________________________________________________ Chemical Analysis of Natural Ferrierite* Locality Itomuka, Kamloops Albero Agoura,** Japan Lake, Bassi, Agoura,** Sonora Pass,** Yajima, Graham Alietti Calif. Calif. Calif. Oxide et al. (1971) (1918) (1967) __________________________________________________________________________ SiO.sub.2 71.21 69.13 56.80 74.40 75.64 66.17 Al.sub.2 O.sub.3 9.84 11.44 12.71 8.51 9.39 10.71 Fe.sub.2 O.sub.3 0.05 3.29 0.04 0.01 0.99 TiO.sub.2 -- 0.10 MnO -- CaO -- none 5.52 0.13 0.14 0.55 MgO 1.70 2.92 4.12 1.07 1.02 2.79 Na.sub.2 O 1.59 3.97 0.27 1.91 2.33 K.sub.2 O 2.85 0.36 0.82 2.48 2.80 1.54 CO.sub.2 -- 2.84 H.sub.2 O(+) 4.25 4.16 13.05 11.46 8.67 17.25 H.sub.2 O (-) 8.63 10.16 __________________________________________________________________________ 100.12 100.87 100.79 100 100 100 __________________________________________________________________________ Chemical Formulae of Ferrierite __________________________________________________________________________ (Na.sub.1.32 K.sub.1.57)Mg.sub.1.09 (Si.sub.30.95 Al.sub.5.03 Fe.sub.0.01).sub.35.99 O.sub.72.01.sup.. 18.82H.sub.2 O (Yajima, et al.) (Na,K).sub. 4 Mg.sub.2 (Si.sub.30 Al.sub.6 )O.sub. 72 (OH).sub.2.sup.. 18H.sub.2 O(Staples, 1955) Na.sub.1.5 Mg.sub.2 Si.sub.30.5 Al.sub.5.5 O.sub.72.sup.. 18H.sub.2 O (Vaughan, 1966) K.sub.0.51 Na.sub.0.25 Ca.sub.0.99 Mg.sub.2.98 (Fe.sub.1.20 Al.sub.7.25 Si.sub.27.50)O.sub.72.sup.. 23.12H.sub.2 O (Alietti, 1967) Na.sub.1.8 K.sub.1.4 Mg.sub.0.6 (Si.sub.31.6 Al.sub.4.4)O.sub.72.sup.. 18H.sub.2 O (Wise et al., 1969) __________________________________________________________________________ *From S. Yajima, et al., Mineralogical Journal, 6 343 (1971). **W. S. Wise, et al., American Mineralogist, 54, 887 (1969).